LMM gear noise in 4x4

[WVRigrat05]

Was driving home last night from Carrollton Ohio to my house (190 miles), drove just over 100 of those miles in four wheel drive.

When I got 20 miles from the house I noticed a gear whining noise when I gave the truck throttle and when I let out of it. No noise just cruising.
I've driven this truck in 4x4 a total of 5 miles prior to this but periodically kicked in and back out just to make sure the shift fork knew where it was at. Truck has right at 70k miles now, all highway, just changed all fluids front to back and top to bottom, and double checked they were topped off before I left town. No evidence of any oil leaks when I got home.

The front end was cool, the spindles were warm, the rear end was just warm enough to melt snow. I did NOT check the transfer case.

 

[ikeG]

It's surprising how many late model trucks i notice this noise in anymore. Just drove a 2012 yesterday home from work in 4wd and it was ridiculous. Has to be transfer case if its doing it while in 4wd.

 

[WVRigrat05]

I'm gonna drain the case tomorrow and check it out, maybe it's where it's never been used until now, didn't need it with all the weight I had in the back but it's a bob sled now.

 

[malibu795]

Speed related or throttle related accel/decell ?
Could have cupped tires pending how worn they are compared to f/r which would be speed only related

Sounds normal temp wise.. For rear diff..
Stock is 4qt some 85/140 from Walmart is what I use
I use synthetic ATF in Trans (2qts)

 

[WVRigrat05]

I'm running synthetic royal purple in diffs and synthetic Mobil 1 5w-30 in the transfer case. It is definitely not my tires, I run mud tires and that ****ing noise never stops. It only does it giving it fuel and when I'm out of the throttle. Zero noise while cruising unless it's a steep hill where it needs more fuel.

 

[malibu795]

Whine under accell/decell be gears..
Does it do it in 2wd? That would eliminate tcase and front diff it it sti whines in 2wd

 

[WVRigrat05]

Don't know, this POS is a bob sled with no weight on ice/snow. Transfer is getting drained tomorrow, fuel cell is going back in and it's going on a ride from hell, so we will see. If it can't handle 100 miles in four wheel drive without the whine my wore out 86' one ton had then I don't want it. I'll find another 05'.

 

[WolfLMM]

My LMM whines in 4wd. It has since new.

 

[WVRigrat05]

Well wtf can it be? I BEAT the **** out of my Raggity old LLY from 35k to 228k miles, changed the the gears in the rearend out once, and changed the fluid in the front end and transfer case once the whole time I owned it. The one time I changed the transfer case, it looked like a girls sparkling fingernail polish, and I put 90w in it at 50k and never touched it again and everything was silent. If it's normal, it is what it is but seems kind of horse shit considering the LMM's transfer is supposed to be an upgrade from the older ones.

 

[WolfLMM]

Well idk, but I do know it's the front diff on mine making noise. Everything checks out good on it, it's just enough to notice. Not loud or annoying.

 

[Mike L.]

Probably a broken snap ring on the main shaft.

 

[Harbin_22]

Probably a broken snap ring on the main shaft.

Mine was broke, but hadn't fallen off all the way yet. Very last snap ring on the output shaft bearing. Towards the rear of truck. Mine was quiet. Just happened to be changing the fluid and found part of the snap ring.

Got any ideas why this happens?

 

[WVRigrat05]

Probably a broken snap ring on the main shaft.

Main shaft on the trans or transfer case?

 

[WVRigrat05]

Well idk, but I do know it's the front diff on mine making noise. Everything checks out good on it, it's just enough to notice. Not loud or annoying.

That's how mine is noise wise. I had turned the radio off and had my window cracked and was going 20 mph, it got quieter the faster I went from what I could tell.

 

[ikeG]

Main shaft on the trans or transfer case?

Transfer case

 

[WVRigrat05]

I tried to make it make the noise today and couldn't get it to do it. Only ran it in four wheel drive a few miles, maybe it wasn't hot enough. Was gonna drain the transfer today but I spent most of the morning trying to get over my cold and finally went to town and got all the salt off my truck and cleaned it again when I got home, so I'll do that in the morning.

 

[chevor]

My 4wd has always been noisy.